Conventionally, with respect to a television broadcast, when the broadcast is received, a program of the broadcast is watched or listened to in real time by an image receiver connected to (or integrally formed with) a receiving device receiving the broadcast, or the program is once recorded by a recording/reproducing apparatus such as a video tape recorder so that the recorded tape or the like is reproduced at an arbitrary time to be watched or listened to.
In any case, conventionally, the received program is only watched or listened to basically as it is, and only a part can be jumped by fast forwarding or the like when the program is recorded on, for example, a video tape and is reproduced.
However, in recent years, according to improvement in performance or reduction in cost of a recording/reproducing apparatus in which a disk (a hard disk, an optical disk, an magneto-optical disk, or the like) is employed as a medium, it has become possible that a disk recording/reproducing apparatus is incorporated in a receiving device for broadcast signals so that the received data of a broadcast program is recorded in the incorporated disk recording/reproducing apparatus and a user reproduces the recorded program data at an arbitrary time.
When the disk recording/reproducing apparatus is employed, since an access to recorded arbitrary data is easy, it is possible to reproduce the data in an arbitrary mode based upon the operation of a user.
On the other hand, in the case of so called digital broadcast in which program data is transmitted from a broadcast station by way of digital data, it is possible to add and transmit various data along with content data that is data of a program content itself, and there has been considered that a reproduction mode of the content data recorded in a digital recording/reproducing apparatus is instructed by utilizing such added data.
For example, when a specific program (suppose it to be content A) is broadcasted, it is supposed that the content A is recorded by a recording device incorporated in a receiving device of a user. Thereafter, when another program (suppose it to be content B) is broadcasted, data which instructs a part of image or the like of the content A to be referred to at the time of watching or listening to the content B is sent from a broadcast station side to a user whose content A is stored in the receiving device, and based upon the data, for example, it is proposed that synthesizing and displaying the image of the content A and the image of the content B can be realized in a receiving device of each user. In the case where a display mode or the like is set according to an instruction based upon the data sent from the broadcast station side described above, basically a user does not need a special operation.
With this, it becomes possible to generate a new content in which contents broadcasted in the past are efficiently utilized, and a new usage mode concerning television broadcast or the like can be established.
However, when the content A broadcasted in the past is processed and utilized at the time of watching and listening to the other content B, there is a risk that the right of the producer or broadcast manufacturer of the content A is infringed. Thus, when such a stored past content is utilized, certain processing such as providing some restriction so as not to infringe a copyright owner or the like of the content A is needed.
Distributing the data of a contents list (an access control list) permitting the content A to be referred to, when the content A is broadcasted, has already been proposed as processing of restricting the usage of past contents, for example. However, there is a problem that predicting how the content A will be utilized in another content in the future is difficult at the time when the content A is broadcasted, and forming data of a complete list of contents which can refer to content A when the content A is distributed is difficult.
Consequently, though it may be possible to keep updating the access control list of the content in the future, it is not practical to manage and update the access control list of an individual content distributed in the past separately, considering management cost or the like.